A passive entry passive start system allows a driver, or anyone who possesses an authorized key fob, to unlock a vehicle's doors as they approach the vehicle without touching a key fob. Once the key fob is within range of the vehicle (e.g., 1 m) locked doors can be open by pulling a door handle. In addition, some PEPS systems can be configured to automatically start the vehicle's engine as an authorized key fob approaches the vehicle. Other PEPS systems require that the driver pushes an ignition button to start and/or stop the vehicle engine.
PEPS systems typically require multiple low frequency (LF) (e.g., 125 kHz) transmitting antennas both inside and outside the vehicle. External antennas can be located in the door handles. In one PEPS system, the key fob detects the low-power signal emitted from the vehicle, and automatically responds by emitting a key code or other identifier. A receiver in the vehicle receives the key code (or other identifier) and sends it to an electronic control unit (ECU). If the key code (or other identifier) is confirmed, the key fob is “authorized,” and the ECU unlocks the doors when the driver touches or pulls on a door handle. To start the vehicle engine, the driver simply pushes an ignition button. The ECU allows the engine to start only when the key fob is detected within the cabin of the vehicle and the key code is confirmed again.
Integration of these antennas and other hardware and wiring needed to implement a PEPS system is costly, and it is always desirable to reduce the cost of vehicles that include such PEPS systems.
In some PEPS systems, system reaction time can be a problem since the key fob must be in close proximity (e.g., within three feet) to the vehicle for it to work. For example, in some conventional PEPS systems, it is often required that an authorized challenge occur within 1 to 3 meters of the vehicle for authentication purposes. In many cases there are delays in a conventional system that can prevent this authorized challenge from completing as the driver begins pulling on the door handle. As a result, the driver may pull the door handle before the door is unlocked. The driver must then release the handle and pull it again for the door to open. It would be desirable to provide a PEPS system that avoids this problem.
In addition, some PEPS systems are insecure and susceptible to relay station attacks. In some cases, the vehicle can be unlocked and/or started without the driver intending the same. As such, it would be desirable to provide more secure PEPS systems that employ more sophisticated security mechanisms.
Another problem that arises in PEPS systems is that in some cases, the key fob is unavailable or does not work. For example, the driver can lose their key fob, or inadvertently lock it in their vehicle. In addition, the key fob authorization process requires that the key fob is operable and can communicate with the vehicle. In such cases, it would be desirable to provide a backup method of unlocking and starting the vehicle.
Accordingly, it is desirable to improved PEPS systems that can help resolve one or more of the drawbacks mentioned above. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.